Retirement Plans (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Service cost	$ 1.1	$ 0.7
Interest cost	3.4	4.7
Expected return on plan assets	(5.8)	(6.3)
Recognized net actuarial loss	2.3	1.0
Settlement loss recognized	0.2	0.0
Net periodic cost	$ 1.2	$ 0.1